What is the Zero-Based Budget?
Zero-based budgeting means income minus allocations equals zero — every rupee is assigned a purpose before the month starts, including savings. Nothing is left "floating", which is where unplanned spending normally hides.
It is more demanding than the 50/30/20 rule but far more precise, and it is the method most likely to expose where money genuinely disappears.
Formula & worked example
Worked example: ₹80,000 income with ₹22,000 housing, ₹12,000 food, ₹6,000 transport, ₹5,000 bills, ₹8,000 debt and ₹20,000 savings = ₹73,000 allocated, leaving ₹7,000 unassigned. That ₹7,000 is exactly the amount that vanishes each month without a plan — assign it to savings or a specific category and the budget balances.
How to use this zero-based budget calculator
- Enter your reliable monthly income, excluding bonuses.
- Fill every category using your last three months of actual spending.
- Treat savings as a bill, not as leftovers.
- Adjust until "Unassigned" reaches zero — that is the whole point.
Smart tips
- Unassigned money is not a surplus; it is next month's mystery expense. Name it now.
- Build the budget from your last three months of statements, not from what you think you spend.
- If you are overspent, cut the largest flexible category first — usually food delivery and subscriptions.
- Redo it monthly. A zero-based budget is a plan for one specific month, not a permanent template.
Frequently asked questions
What is zero-based budgeting?
A method where you allocate every rupee of income to a category — spending, saving or debt — until nothing is unassigned. The balance must reach exactly zero.
Is zero-based budgeting better than 50/30/20?
It is more accurate and better for tight budgets or irregular income. 50/30/20 is simpler and easier to sustain long-term.
What if I have money left over?
Assign it deliberately — to savings, debt or a sinking fund. Leftover money with no name is the most common source of budget leaks.
How do I zero-base an irregular income?
Budget on your lowest recent month. Allocate surplus from better months to a buffer fund that smooths the weak ones.
Want the theory behind the numbers? Read our budgeting guides on the Money Blog.
Written by Gurjeet Singh, Sharpen Solutions. Last reviewed 30 Sep 2026. How we check these numbers.